Tobacco



TOBACCO Samuel OBrien Jones, Winston-Salem, N. C., assignor to R. J. Reynolds Tobacco Company, Winston-Salem, N. C., a corporation of New Jersey No Drawing. Application July 26, 1954, Serial N0. 445,891

41 Claims. (Cl. 131-17) This invention relates to tobacco and has for an ob ject the provision of a smoking tobacco product having improved aroma and flavor characteristics which become apparent during smoking.

Smoking tobacco as now prepared for use in cigarettes comprises essentially a blended mixture of various types of tobaccos which are desired to produce a characteristic flavor and aroma when the tobacco is smoked. Present day cigarette tobaccos normally comprise blends of (l) heat-cured tobaccos, which are sometimes known as flue-cured, bright leaf or Virginia tobaccos, (2) aircured tobaccos, which are sometimes known as burley or Kentucky and Maryland tobaccos, and (3) sun-cured tobaccos, which are known as Turkish or Oriental tobaccos. The relative proportions of these various types blended to produce a desired cigarette tobacco mixture depend in a large measure upon the characteristic flavor or aroma that is desired to be achieved when the tobacco is smoked. Also it is common practice to add various substances, such as flavoring materials and humectants, in order to provide other desired properties.

A further object of this invention is to provide a smoking tobacco which when smoked will have improved or enhanced flavor and odor characteristics which will be pleasing to the smoker.

A further object of this invention is the provision of a smoking tobacco having added thereto a compound or compounds which, when the tobacco is smoked, will liberate one or more organic acids imparting a selected and desired flavor and aroma to the smoke.

A still further object of this invention is the provision of a tobacco product having added thereto a substantially nonvolatile substance which in itself does not substantially change the flavor or aroma of the tobacco but which when burned on the tobacco will release to the smoke certain desired flavoror aroma-producing acids.

A still further object of this invention is the provision of a tobacco having added thereto an organic compound which, when the tobacco is smoked or burned, will liberate several types of flavoring acids whereby the desired improvement in the flavor and aroma of the smoke may be achieved.

A still further object of this invention is to provision of additives for tobacco which may be easily and simply prepared and which may be incorporated into the tobacco at any stage during the processing thereof.

A further object of this invention is the provision of a tobacco containing an additive which is a derivative of certain compounds (e. g. sugars) normally found in tobacco, said derivative being one which will release a flavorproducing acid when the tobacco is smoked.

Further and additional objects will appear from the following description and the appended claims.

In accordance with the broad aspects of this invention, a smoking tobacco composition is provided which contains as an additive a small amount of a substance which when burned or smoked with the tobacco will release one or more organic flavoring acids preferably having from 3 to 8 carbon atoms. Thus I have found that these acids, when present in the smoke in suitable concentrations, will impart characteristic and desirable flavor and aroma to the tobacco smoke, thus contributing to the enjoyment of the smoker. Preferably the tobacco additive itself is substantially nonvolatile under ordinary tobacco storage conditions so that it will remain dispersed throughout the tobacco until such time as it is smoked and it is preferably sufliciently nonvolatile so that it will remain in the burning area of the tobacco to permit the acid release to occur. Obviously it should not volatilize much ahead of the burning zone or the desired acid release may not occur. It is also preferred that the additive be sufliciently stable so that the main portion of it will be present in the tobacco for releasing the acid at the time the tobacco is smoked or burned.

The flavor-producing acids which are released by the additives in accordance with this invention are preferably those flavoring acids which will volatilize and will be carried by the smoke, such acids usually being the organic carboXylic acids having 3, 4, 5, 6, 7 or 8 carbon atoms, herein collectively referred to as those having from 3 to 8 carbon atoms. Representative acids are the saturated aliphatic fatty acids, such as propionic, n-butyric, isobutyric, n-valeric, isovaleric, 2-methylbutyric, n-caproic, 4-methylvaleric, 3-methylvaleric, 2,2-dimethylbutyric, 2- methylisovaleric, straight or branched chain heptoic, or straight or branched chain caprylic acids; the unsaturated aliphatic fatty acids, such as acrylic, crotonic, vinylacetic, 4-methyl-4-hexenoic and S-methylsorbic acids; the cycloalkane or cycloalkene aliphatic acids, such as cyclopentanecarboxylic, cyclohexanecarboxylic, cyclopentaneacetic or cyclohexaneacetic acids or the corresponding unsaturated cycloalkenes; the aromatic carboxylic acids, such as benzoic or toluic acids; and phenylacetic acid. Also the volatile derivatives of such acids as the hydroxy acids or keto acids may be the acid compounds released to impart the desired odor or flavor to the smoke. It is preferred that the flavoring acid be an aliphatic or alicyclic saturated monocarboxylic acid of the fatty acid series having 4, 5 or 6 carbon atoms, herein collectively referred to as those having from 4 to 6 atoms.

As previously indicated, the additive incorporated into the tobacco in accordance with this invention is one which, when the tobacco is burned or smoked, will release one or more of the foregoing types of flavoring acids during smoking or burning and it is preferred that the additive itself be one which will not release the acid until such time as the tobacco is smoked. As will become apparent in the following, the additive may be selected or prepared in such a manner that any one of the types of the foregoing acids will be released during smoking. Also a single additive or mixture of additives may be selected and added to the tobacco so that a plurality of desired flavoring acids may be simultaneously liberated if desired, thus effecting a blend of the various types of aromas which has the characteristics of the several flavoring acids. As previously mentioned, the additive itself should be relatively nonvolatile since it should remain in the tobacco during storage so that it will be available to decompose upon smoking to liberate 3 may also produce other characteristic llavorand aromaproducing substances.

Additives that have been found to be particularly suitable for incorporating into a tobacco in accordance with this invention are esters of the above indicated flavoring acids. However, other compounds may be employed which during smoking of the tobacco will liberate the flavoring acids. Such other compounds are the alkylated or arylated derivatives of malonic acid and certain aliwherein RCOOH-represents the liberated flavorand aroma-producing acid and R represents hydrogen, an organic radical or other substituent. In the case where the additive comprises a derivative of malonic acid the liberation of the flavoring acid on smoking may be accounted for by a decarboxylation reaction of the type:

/COOH RCH T RCHz-COOH 002 wherein RCH2-COOH represents the flavoring acid. In the case Where the additive comprises a 1,3-diltetone or a derivative thereof, the acid released may be accounted for by splitting of the molecule and hydrolysis adjacent one of the carbonyl groups in accordance with the following generalized reaction:

R"Cl-CH2'\3-R RHfi-CH -l- R-COOH Where RCOOH represents the flavoring acid and R represents an organic radical. In the generalized reactions indicated above the symbol A indicates that the designated reactions take place when the compounds are heated as during smoking of the tobacco containing the specified additives. In reactions (2) and (4) the symbol H2O indicates that Water takes part in the reactions.

However, as previously indicated, the additive is preferably an ester of the flavoring acid and a hydroxyl group-containing compound. The hydroxyl compounds which are esterified with the flavoring acid are preferably organic innature and are in general related to the alcohols, glycols, phenols and their derivatives. The hydroxy compounds may be aliphatic, aromatic, cyclic or acyclic in nature. If they are cyclic, they may be homocyclic or heterocyclic. Furthermore, the hydroxy compounds may be monohydric or polyhydric in nature and,if polyhydric, the hydroxyl groups may be fully or partially esterified with one or more flavoring acids or with flavoring and nonflavoring acids. A particular advantage in the acylated derivatives. Representativeesters of this type are: decyl isovalerate, decyl 4-methylvalerate, linalyl isovalerate, the isovaleric acid ester of diacetone alcohol and 3-acetylpropyl 4-methylvalerate.

(2) The aliphatic hydroxy acids and their derivatives. Representative esters of hydroxy compounds of this type are: 2-carbethoxy-l-methylethyl cyclohexanecarboxylate, Z-carbethoxy-l-isopropylethyl 4-methylvalerate, the isovalerate of 4-hydroXy-4-valerolactone,' mucic 'acidtetraisovalerate, tartaric acid diisovalerate, tartaric acid bis(4- methylvalerate), malic acid isovalerate, malic acid 4- methylvalerate, citric acid 3-rnethylvalerate, citric acid 4- methylvalerate and diethyl malate 4-methylvalerate.

(3) The polyhydric alcohols and their derivatives. Representative esters of this type are: ethylidene bis(4- methylvalerate), triethylene glycol diisovalerate, glyceryl mono(4-'nethylvalerate), glyceryl monoisovalerate, glyceryl triisovalerate, glycerol phenyl ether. bis(phenylacetate), glycerol phenyl ether bis(3-methylvaierate), 2- methyl-2,4-pentanediol diisovalerate, sorbitol hexaisovah crate. As previously indicated, these polyhydroxy compounds are particularly useful since they may be partially or fully esterified with one or more flavor-producing acids.

(4) The alicyclic hydroxy compounds, such as the monoor polyhydroxy cyclohexanes, cyclohexenes. cyiclopentanes or cyclopentenes and their derivatives. Representative esters of this type are: meta-methylcyclohexyl isovalerate, the tris(3-methylvalerate) of 1,2,8-trihydroxyrnenthane, 2-isopropyl-S-methyl-l-isopentylcyclohexuse of polyhydric alcohols or other polyhydroxy compounds as the ester-forming compound is that a plurality of selected flavoring acids may be used to esterify the several hydroxyl groups, thereby permitting a wide selection of flavor and aroma characteristics inthe smoke from a tobacco containing such an additive,

Examples of various kinds and types of hydroxyl compounds Which may be esterified with the flavoring acid to produce an additive for use in accordance with certain embodiments of this invention are:

(1) The saturated or unsaturated acyclic aliphatic monohydric alcohols or their derivatives such as certain yl 4-methylvalerate, inositol isovalerate, elemyl isovalerate, terpin bis(4-methylvalerate), terpin mono(4-methylvalerate), terpin diisovalerate, terpineol isovalerate, cedryl 4-methylvalerate and the isovalerates of the varioussterols and their derivatives such as the soy sterols.

(S) The aromatic hydroxy compounds, such as phenolic type compounds and their derivatives, or substituted aromatic compounds where the hydrot-iyl group .is positioned on a side chain. Representative esters of this type are catechol mono(4-rnethylvalerate) pyrogallol mono(4- methylvalerate), salicyciic acid isovalerate, anisyl isovalerate, santyl 4-methylvalerate, eugenol isovalerate, eugenol 4-methylvalerate, eugenol cyclohexanecarboxylate, 3- ethoXy-4-hydroxybenzyl isovalerate, l-phenylethyl isovalcrate, Z-carbethoxy-i-phenylethyl cyclohexanecarboxylate, benzoin cyclohexanecarboxylate, phenethyl 4-methylvalercrate, and 3-phenylpropyl 4-methylvalerate.

(6) The heterocyclic alcohols, such as the various hydroxy derivatives of furane, thiophcne, pyrrole, pyridine, pyroue, orcondensed heterocyclic ring compounds, such as iudole. Representative esters of this typearet, furfuryl isovalerate, furfuryl 4-methylvalerate, furfuryl benzoate and furfuryl phenylacetate.

(7) Carbohydrate type compounds such as'sugars and their derivatives. The esters of carbohydrate type compounds have been found to be particularly suitable as tobacco additives in accordance with this invention. The hydroxyl groups of these compounds may be Wholly or partially esterified With one or more of the flavoring acids. The sugars include the mono-, diand polysaccharides and may either be aldoses as exemplified by glucose, or ketoses asexemplified by fructose. Represeutative'esters of sugars and their derivatives are: glucose pentapropionate, glucose pentaisobutyrate, glucose pentakis(2-methylbutyrate), glucose pentaisovalerate, glucose .pentakis(3- methylbutyrate), glucose pentakis(4-methylvalerate), glucose pentacyclopentanecarboxylate, glucose pentacyclohexanecarboxylate, glucose 1-isovalerate-2,3,4,6-tetraacetate, alpha-methyl-d-glucoside isovalerate, beta-glucose isovalerate, fructose pentaisovalerate, fructose pentakis (4-methylvalerate), sucrose triisovalerate, sucrose octaisovalerate, sucrose octa(4-methylvaierate), sucrose tetraisovalerate and pentaisovalerate (a miXture),-and lactose octacyclopentanecarboxylate.

It will be appreeiated from the foregoing that-there are a large number of hydroztyl compounds'which may be esterified with the flavor-producing acid in order to produce an additive which when added to tobacco will release the flavor-producing acid during smoking. The specific flavor-producing acid that is combined with the hydroxy compound to form the ester will depend upon the flavor and aroma desired in the tobacco smoke. As indicated above, the particular acid selected for the preparation of the ester is of consequence only in so far as the particular flavor contributed by that particular acid is important. Any of the flavor-producing acids may be utilized and, as previously indicated, they generally comprise the saturated or unsaturated organic carboxylic acids containing from 3 to 8 carbon atoms.

The additives contemplated by this invention may be incorporated into the tobacco in any desired manner. For example, solutions of the additive in a suitable solvent, such as alcohol, ethyl ether, acetone or the like, may be applied to the tobacco as by spraying or otherwise, whereafter the solvent is driven oil? as a vapor leaving the additive thoroughly incorporated with the tobacco. The additive may also be uniformly dispersed in water and applied in a like manner if desired. The incorporation of the additive may take place at any time prior to the final packaging of the tobacco product. In the case of cigarette tobacco, it may be incorporated before or after blending of the various tobaccos if, in fact, blended tobacco is employed, and the additives may be applied to one or all of the blend constituents. Under certain circumstances the additives may be incorporated into the tobacco before aging and curing; however, this would not ordinarily be done if the additive has a tendency to decompose during the aging and curing process. In the case of cigarettes the additives in some instances might be applied to the paper instead of to the tobacco.

The amount of additive in the final tobacco product contemplated by this invention is quite small but will vary widely with the particular additive employed and the amount of acid flavor or aroma desired in the smoke. Thus an additive that releases only a comparatively small fraction of its total available flavoring acid on burning will be required in higher concentrations than those additives which are more efficient with respect to the amount of flavoring acid released. Also it is well known that some of the aliphatic fatty acids having from 4 to 6 carbon atoms have a disagreeable odor per se when vapors of these acids are smelled in certain concentrations. However, in very low concentrations they provide in the tobacco smoke a desirable flavor and aroma, and the amount of additive in the tobacco should be such as not to exceed the amount which, when" the tobacco is smoked, will release desirable quantities of the acid. This amount in many cases will be determined by actual experimentation. Generally speaking, however, desirable flavor and aroma are produced if the additives are incorporated into the final tobacco product in amounts between about 0.0l and 1.0 percent by weight (dry basis).

In evaluating the various types of compounds contemplated within the scope of this invention, a number of methods were employed for incorporating the additive into cigarette tobacco and certain of such methods are further suggestive of procedures that may be used in actual commercial practice. The following are specific examples of methods that were used:

METHOD 1 One gram of shredded flue-cured tobacco was spread out on a watch glass of 10 cm. diameter. One milliliter of a solution of the additive in a suitable solvent such as ethyl ether was added uniformly to the tobacco from a pipette. The amounts of the additives vary but in general 10 milligrams of additive were applied to the onegram sample. After the ether had evaporated the tobacco was rolled into a cigarette which was stored at 75 F. and about 60% relative humidity.

METHOD 2 A small quantity of liquid additive in the amount of l to 5 milligrams was streaked longitudinally along the paper of a cigarette by means of a stirring rod.

METHOD 3 The additive was dissolved in a volatile solvent, such as acetone, alcohol or ether, using 2 to 40 milligrams of additive per milliliter of solvent. One fourth milliliter of the resulting solution Was then distributed through a one inch portion (which was to be burned) of a cigarette by means of a A milliliter hypodermic syringe. The volatile solvent was then blown out of the cigarette with a stream of compressed air, leaving the additive dispersed in the cigarette.

METHOD 4 The additive was dissolved in ethyl alcohol or other suitable solvent and sprayed onto shredded flue-cured tobacco spread out on a table. Two hundred milliliters of solution containing 1 to 20 grams of additive were used for each 3 kilograms of tobacco. The tobacco was exposed to the air until substantially all of the solvent had evaporated and then was manufactured into cigarettes in the usual manner havingan average weight of one gram each. These were stored for a period of 1 to 12 months at 75 F. and 60% relative humidity in order to ascertain the stability of the additive when stored on tobacco.

METHOD 5 The additive was dissolved in alcohol or other suitable solvent and sprayed onto one of the types of leaf tobacco that is used in a blended cigarette. This leaf tobacco was allowed to dry and was cut on a shredding machine. The shredded tobacco was blended with other types of shredded tobacco that had not been treated with additive and the blend was made into cigarettes.

The compound or additive under test when applied to a low flavor tobacco or a cigarette made therefrom as indicated in one of the foregoing methods was evaluated by organoleptic testing. This was carried out by smoking the cigarette and examining the smoke by sensory methods. In each of these tests special efforts were made to determine whether any acid odor was present in the smoke. This included a careful sensory study of both the main stream and the side stream. If the acid odor was detected in either the side stream or the main stream, it was concluded that the additive released the acid during the smoking or burning of the treated tobacco or cigarette.

In the foregoing, specific reference has been made to general classes of compounds and specific examples thereof which are useful as additives for. tobacco in accordance with this invention. Certain of these compounds are new and certain of them are not available commercially. Accordingly, a number of examples will be presented in the following which are representative of methods of preparing certain of these compounds. All of the compounds which were prepared by the specific procedures given in the examples to follow were tested by one or more of the methods previously mentioned and were found to release flavoring acid when smoked with tobacco. It will be understood that in certain instances an example is given of preparing an additive which will, upon burning or smoking of the tobacco treated therewith, liberate only one of the flavor-producing acids contemplated by this invention. However, it will be apparent to one skilled in the art how other additives releasing other particular flavoring acids may be prepared. For example, in the following where there are given examples of processes of preparing esters of isovaleric acid it will be understood that essentially the same or similar means known to chemists could be employed for preparing the esters of other flavoring acids of the character hereinfollowed by refluxing for 3 hours.

-by distillation until the vapor temperature reached 100 This Isobutylmalonic acid To 200 milliliters .of absolute ethanol were added, with stirring, 17.5 grams of sodium methylate. After solution, followedj-by cooling to50". C., 50 grams of diethyl malonate were added slowly withstirring; "Over a period of 2 hours, 41.1 grams of isobutyl bromide were added .dropwise, and the mixture was refluxed for hours. The alcohol was distilled off until the vapor temperature reached 100 C., and then 150 milliliters of water were I added. The organic layer was separated and the water layer was extracted twice with 50 milliliters of. ether which were added to the organic layer. tion was concentrated in vacuo. The residue was added dropwise to 50 grams of potassium hydroxide dissolved in 150 milliliters of warm water over a period of hour; Alcohol was removed C. An equivalent amount of sulfuric acid plus enough acid to neutralize the excess base was added and the isobutylrnalonic acid removed by continuous ether extraction. On concentration of the ether, solution, the

-white crystalline solid, M. P. 1067 C., was obtained in about 65 yield.

This compound releases isocaproic acid when smoked in a cigarette, presumably in accordance with Equation 3 given above.

8-methyl-2,3,5-n0nanetri0ne To 3.9 grams of sodamide in 30 milliliters of benzene were added ;slowly 8.6 grams of 2,3-butanedione (biacetyl), followed by 13.4 grams 4-methylvaleryl chloride. The benzene solution was washed with dilute acid and dilute base and concentrated in vacuo to give grams of oil.

This compound comprising 8-methyl-2,3,5-nonanetri one releases acid on smoking of cigarette tobacco, presumably in accordance with Equation 4 given above.

2,1Z-dimethyl-4,7,9-tridecanetrione Reacted in the same way as in the preparation of 8-methyl-2,3,S-nonanetrione were 5.1 grams of 7-rnethyl- 2,5-octanedione, 1.3 grams of sodamide, and 4.5 grams 4-methylvaleryl chloride in 30 milliliters of benzene. The yield was 6 grams of oil.

compound comprising 2,12-dimethyl-4,7,9-tridecanetrione releases acid upon smoking of tobacco treated therewith, presumably in accordance with Equation 4 given above.

Decyl isovalerate A solution of 10 grams of normal decyl alcohol in 10 milliliters of pyridine was cooled to 0 C., 12 grams of .:.isovaleryl chloride were added dropwise with stirring, .and the mixture was allowed to come to room temperature and stand for one hour.

The reaction product was diluted with water and extracted with ether. The ether layer was washed successively with dilute ammonia,

z-dilute hydrochloric acid, and water and was dried over The. ether was removed and anhydrous sodium sulfate. the residue distilled.

3acetr0pr0pyl 4-methylvaleratc as in the preparation of glyceryl triisovalerate (see below), but using tenth quantities. A 1.5 gram yield of the oil ester was obtained.

Z-carbethoxy-I-is0pr0pylethyl 4-methylvalerate As in the preparation of glyceryl triisovalerate (see The ether solubelow) 2:6 grams of ethyl 3-hydroxy-4-methylvalerate,

' made-by the Reformatsky condensation of isobutyralde- 'hyde with ethyl bromoacetate, 2.7 grams 4-methylvaleryl chloride, and 1.6 grams pyridine were reacted. A 65% A mixture of 15 grams of tartaric acid and 36 grams of isovaleryl chloride was heated in an oil bath at 110- 125 for 3.5 hours and then allowed to stand overnight. The solid reaction mixture was washed with 150 milliliters of hexane. The insoluble material was extracted with 100 milliliters of hot benzene. The benzene solution was diluted with hexane. After 3 hours the solid was collected by filtration and dried to give 10 grams of product which melted at 73 to 75 C. The solid was dissolved in a mixture of hexane and toluene, filtered, and the filtrate was diluted with hexane. The precipitate was removed by filtration and dried to give 6.4 grams of product which melted at 88 to 90 C. Infrared analysis of the crystalline product showed the presence of ester and carboxylic acid bonds but no anhydride bonds. Calculated for C14H22Oa2 C=52.82, H=6.96. Found: C =53.19, H=6.96.

Malic acid 4-methylvalerate A mixture of 13.4 grams of dl-malic acid and 31 grams of 4-methylvaleryl chloride was heated gradually to 120 solvent (Skellysolve B).

C. After 3 hours at this temperature, the reaction mixture was poured into 150 milliliters of a hydrocarbon The oil which separated was dissolved in hot benzene, and Skellysolve B added until a slight turbidity appeared. The solution was concentrated in vacuo to a solid residue. The solid, malic anhydride 4-methylvalerate, was purified by recrystallization from a toluene-Skellysolve B mixture. It was hydrolyzed with an equivalent of water and recrystallized from chloroform, giving a 65 yield of the crystalline malic acid 4-rnethylvalerate.

Citric acid 4-methylvalerate A mixture of 19 grams of anhydrous citric acid and 54 grams of 4-methylvaleryl chloride was treated as in the preparation of malic acid 4-methylvalerate (see above). A 55 yield of crystalline citric acid 4-methylvalerate was obtained from the anhydride upon hydrolysis.

Diethyl malaze 4-methylvalerate A mixture of 47.5 grams of diethyl malate, 20 grams of pyridine,'and milliliters of chloroform was treated with 35 grams of 4-rnethylvaleryl chloride as in the preparation of glyceryl triisovalerate (see below). Distillation under reduced pressure gave an 80% yield of the oily ester.

Glyceryl monoisovalerate .A mixture of 1.1 mole (121.5 grams) of glyceryl alphachlorohydrin and 1.0 mole (124 grams) of sodium isovalerate was heated at -1 12 C. for 5 hours. The precipitated sodium chloride was filtered and washed with ether. The ether solution was concentrated in vacuo and the residue distilledunder reduced pressure giving a 59% yield of the oily ester, B. P. -7 C. at 3.5 mm.

Glyceryl triisovalerate To 2.2 grams of glycerine, 5.6 grams of pyridine and 100 milliliters of chloroform cooled in an ice bath were added slowly with stirring 9.0 grams of isovaleryl chloride. After warming slowly to room temperature, the reaction mixture was refluxed for 2 hours. After cooling,.the mixture was diluted with 250 milliliters of ether and washed successively with 100 milliliters of water, 100 milliliters of 2 N sulfuric acid, 100 milliliters of water, two 100-milliliter portions of 5 %.NaHCO3 solution, and 100 milliliters of water; 'After drying with calcium chloride, the ether solution was concentrated in vacuo, and the residue distilled under reduced pressure, giving a 65% yield of light yellow oil, B. P. 153-6 C. at 2 mm.

Sorbitol hexaisovalerate A mixture of 45.5 grams of sorbitol, 120 grams of pyridine and 350 milliliters of chloroform was treated with 185 grams of isovaleryl chloride as in the preparation of glycerine triisovalerate (see above), except that the reaction mixture was diluted with 1250 milliliters of ether and the wash solutions were used in 300-milliliter portions. Purification by molecular distillation gave a 60% yield of the oily ester.

This compound was also prepared as follows: A mixture of 10 grams of sorbitol, 100 milliliters of isovaleric anhydride, and 57 milliliters of pyridine was stirred for 7 hours and allowed to stand for 6 days. The reaction product was diluted with water and extracted with ether. The ether layer was successively washed with dilute HCl, dilute ammonia, water, and dried over anhydrous sodium sulfate. The ether was removed in vacuo to give 30 grams of product. An analysis by the Craig countercurrent distribution technique indicated that the product was 60 per cent sorbitol hexaisovalerate and 40 per cent sorbitol pentaisovalerate.

Terpin diisovalerate A mixture containing 8.6 grams of terpin, 1O milliliters of nicotine, and 15.5 milliliters of isovaleryl chloride was stirred for 5 hours at room temperature and then for 11 hours at 55 C. The reaction product was diluted with water and extracted with ether. The ether layer was washed successively with dilute HCl, dilute ammonia, water and dried over anhydrous sodium sulfate. The ether was removed and the residue was distilled from a pot-type molecular still to give 12.9 grams of product. Saponification data indicated that the product was about 70 per cent terpin diisovalerate and 30 per cent terpin monoisovalerate. This compound, in addition to releasing acid, also gives rise to a piney flavor or odor when smoked with tobacco, which is desirable to some smokers.

Terpin mono (4-methylvalerate) A mixture of 3.5 grams of terpin, 2.0 grams of powdered magnesium, 6 milliliters of 4-methylvaleryl chloride, and 15 milliliters of anhydrous ether was allowed to stand for 24 hours with frequent shaking. The reaction product was diluted with water and extracted with ether. The ether layer was Washed successively with dilute HCl, dilute ammonia, water, and dried over anhydrous sodium sulfate. The ether was removed and the residue was distilled in vacuo to give 2.9 grams of product. This compounds also imparts a piney character to the smoke in addition to the acid flavor when burned or smoked with tobacco.

Cedryl 4-methylvalerate Cedrol was treated with an excess of pyridine and 4- methylvaleryl chloride. The reaction mixture was worked up as in the preparation of glyceryl triisovalerate (see above).

Isovalerates of soy sterols These compounds (a mixture) were made from soy sterols by a procedure similar to that described above for the preparation of terpin diisovalerate.

Phenethyl 4-methylvalerate This compound was prepared by a procedure similar to that described below for the preparation of furfuryl isovalerate.

Eugenol isovalerate To a cooled mixture of 19.5 grams of eugenol, 100 milliliters of chloroform and 10 milliliters of pyridine were added dropwise, with stirring, 18.0 grams of isovaleryl chloride. After the reaction mixture warmed to room temperature, it was heated under reflux for two hours. The reaction mixture was diluted with-250 milliliters of ether and the ethereal solution was washed successively with 100 milliliters of water, 100 milliliters of 2 N sulfuric acid, 100 milliliters of water, two 100-milliliter portions of 5 per cent sodium bicarbonate and 100 milliliters of water. After the ethereal solution was dried over calcium chloride, the low-boiling solvents were removed by distillation at reduced pressure and the product was crystallized from methyl alcohol and hexane.

F urfuryl isovalerate A solution of 10 grams of furfuryl alcohol in 10 milliliters of pyridine was cooled to 0 C. Isovaleryl chloride (12 grams) was added dropwise, with stirring, and the mixture was allowed to come to room temperature and to stand for one hour. The reaction product was diluted with water and extracted with ether. The ether layer was washed successively with dilute ammonia, dilute HCl and water, and dried over anhydrous sodium sulfate. The ether was removed and the residue was distilled in vacuo to give 12 grams of light yellow oil.

Glucose pcntaisovalerate To a chilled mixture of 7.2 grams of glucose, 20 milliliters of pyridine, and 100 milliliters of chloroform were added dropwise with stirring 25.5 grams of isovaleryl chloride. After warming slowly to room temperature the reaction mixture was refluxed for 6 hours. After cooling it was diluted with 300 milliliters of ether and Washed successively with 100 milliliters of water, 100 milliliters of 2 N sulfuric acid, 100 milliliters of water, two 100-milliliter portions of 5% NaHCOa solution, and 100 milliliters of water. The ethereal solution was dried with anhydrous calcium chloride and concentrated in vacuo. Recrystallization of the residue from methanol gave 11.1 grams of a white crystalline solid, M. P. 55.5-57.5 C.; yield, 46%.

Fructose pentaisovalerate A mixture of 0.5 grams of freshly fused zinc chloride, 5 grams of finely powdered fructose and 75 milliliters of isovaleric anhydride was shaken intermittently for 20 days. The excess isovaleric anhydride was removed in vacuo at 50. The residue was diluted with water and extracted with ether. The ether layer was successively washed with dilute ammonia and water, and then dried over anhydrous sodium sulfate. The ether was removed in vacuo to give 14.6 grams of product.

Sucrose oczaisovalerate A mixture of 5 grams of finely ground sucrose, 4 milliliters of isovaleryl chloride, and 0.5 milliliter of pyridine was allowed to stand for about 70 hours. The reaction product was diluted with water and extracted with ether. The ether layer was washed successively with dilute ammonia, dilute HCl and water, and then dried over anhydrous sodium sulfate. The ether was removed in vacuo to give 2.2 grams of product.

It will be understood that the foregoing specific examples are only representative of the large number of compounds that have been prepared and tested for acid release on smoking of a tobacco treated therewith. It will be understood that the foregoing compounds may be prepared by other methods that are well known to the art generally. The specific examples given are believed to be adequate to show the manner in which a large number of esters of the various 'hydroxy compounds and the several flavoring acids may be readily prepared.

A specific example of a method of incorporating the additive into a cigarette tobacco is as follows: Three hundred grams of tobacco strips were spread out on a table and were sprayed with a solution of 1.5 grams of glucose isovalerate in milliliters of alcohol. The treated strips were then mixed with 900 grams of burley strips and 1800 grams of flue-cured strips, and the entire "assigneda rating of 10..

blend was shredded on a tobaccorcut-ting,rnachine. The

" shredded mixture was manufactured into --cigarettes, These cigarettes were stored in a room maintained at 75 F. and 60% relative humidity. A testshortly after manufacture by a panel of smokers and subsequent tests at the end of 60, 150 and 220 days showed that isovaleric acid was present in'thc smoke from thecigarettes in pleasing amounts.

Studies have been made inorderto determine the extent to which the compounds comprehended-by this invention will. actually release acid when smoked with tobacco. In these tests an arbitrary scale has been set up for comparing a large number of the various additives that have been preparedand incorporated int o tobacco in accordance with this invention; The additives which liberatethe largest amount of acid on organeleptic test basisrduring smoking have been arbitrarily The additives at the bottom of the scale liberating detectable but small quantities of acidon'an o'rganoleptic test basis have been assigned a'rating of 1. Using this arbitrary scale and evaluating the various additives bya'test-panel of a number of smokers, the following ratings were arrived at for certain specific compounds contemplated within the scope of this invention:

RATING 1o Tartaric acid diisovalerate Malic acid isovalerate Malic acid 4-methylvalerate Citric acid 3-rnethylvalerate Citric acid 4-rnethylvalerate RATING 8 Fructose pentaisovalerate Fructose pentakis(4-methylvalerate) RATING 7 Benzoin cyclohexanecarboxylate RATING 6 Z-carbethoxy-l-methylcthyl cyclohexanecarboxylate Z-carbethoxy-l-phenylethyl cyclohexanecarboxylate Glucose pentakis(4-methylvale-rate) Glucose pentakis(3-methylvalerate) Glucose pentaisovalerate Glucose pentapropionate Glucose pentakis Z-methylbutyrate) Glucose pentaisobutyrate Glucose pentacyclopentanecarboxylate Glucose pentacyclohexanecarboxylate RATING Mucic acid tetraisovalerate Terpin diisovalerate Eugenol cyclohexanecarboxylate Salicylic acid isovalerate Glucose-l-isovalerate-2,3,4,6-tetraacetate Lactose octacyclopentanecarboxylate RATING 4 Sucrose tetra and penta isovalerate (mixture) RATING 3 Terpineol isovalerate Sucrose octaisovalerate Sucrose triisovalerate RATING 2 Glyceryl monoisovalerate Linalyl isovalerate .Z-methyl-2,4 pentanediol diisovalerate RATING 1 Sorbitol hexaisovalerate Glyceryl triisovale-rate Glyceryl phenyl ether bis(phenylacetate) Glyceryl phenyl ether bis(3-methylvalerate) lsovaleric acid ester of diacetone mcohol Triethylenc glycol diisovalerate A]pha-methyl-d-giucoside isovalerate Inositol isovalerate Anisyl isovalerate of acidrelease, they are not necessarily conclusive in evaluating the particular compound for commercial use as a tobacco additive in accordance with this invention. For example, some compounds having a high rating may have a tendency to be unstable under tobacco storage conditions, thereby prematurely releasing the acid, it being understood that it is generally desirable for the acid not to be released prior to smoking. Partly for this reason the esters of the carbohydrates and particularly the esters of the monoand disaccharides, such as glucose, fructose and sucrose, are particularly'useful as additives for tobacco. Also these particular carbohydrates or their derivatives are naturally-occurring in tobacco and the presence of them or of their derivatives as a residue after the acid has been released does not introduce any foreign constituent into the tobacco during the smoking procedure.

Also, in accordance with this invention, it is in certain instances preferred to employ an ester of a polyhydroxy compound wherein more than one of the hydroxyl groups is esterified with the flavoring acid, since, at least theoretically, such compounds are capable of releasing more than one molecule of flavoring acid per molecule of the ester. Thus, on a weight for weight basis, the poly esters may be more effective than the corresponding mono esters. Generally, however, the degree of acid release in each instance should be tested by actual trial since, as the foregoing rating scale indicates, the degree of acid release does not always appear to be directly proportional to the number of esterified groups in the hydroxy compound.

It will be understood that compositions have been prepared in accordance with this invention which have improved or enhanced aroma and flavor to give increased pleasure during smoking. Infinite variations with respect to the kinds and amounts of flavor-producing acids are possible and may be readily controlled. Such flavorproducing additives may be particularly useful with tobaccos which are ordinarily low in the type of flavor imparted by the flavoring acids. While the invention has been specifically described with reference to cigarettes, it will be apparent that it has application in the manufacture of other smoking tobaccos such as used for handrolled cigarettes, pipes and cigars.

While several particular embodiments of this invention :are shown above, it will beunderstood, of course, that the invention is not to be limited thereto, since many modifications may be made, and it is contemplated, therefore, by the appended claims, to coverany such modifications as fall within the true spirit and scopeof this invention.

I. claim:

:a monocarboxylic acid.

4. A smoking tobacco having-added thereto a small amount of a substantially nonvolatile substance relatively stable under normal tobacco storage conditions but which substance will, upon smoking with the tobacco, release in the smoke a volatile flavor-producing acid having from oia hydroxy acid compound in whichthe hydroxyl group thereof is esterified with a flavor-producing organic acid, said ester being decomposable upon burning of said tobacco to release said flavor-producing acid.

7. The tobacco recited in claim 6 wherein said hydroxy acid compound is selected from the group consisting of compounds of tartaric acid, malic acid and citric acid.

8. A smoking tobacco having added thereto a small amount of a substantially nonvolatile ester of a polyhydroxy compound and a volatile flavor-producing organic acid.

9. A smoking tobacco having added thereto a small amount of a substantially nonvolatile substance comprising an aliphatic polyhydroxy compound at least partially esterified with a volatile flavor-producing organic acid having from 3 to 8 carbon atoms.

10. A smoking tobacco having added thereto a small amount of a carbohydrate at least partially esterified with a volatile flavor-producing organic acid.

11. The tobacco recited in claim 10 wherein said esterified carbohydrate is a sugar ester.

12. The tobacco recited in claim 10 wherein said esterified carbohydrate is an ester of a disaccharide.

13. The tobacco recited in claim 10 wherein said esteritied carbohydrate is an ester of a monosaccharide.

14. A smoking tobacco having added thereto a small amount of a sugar compound at least partially esterified with a volatile flavor-producing organic acid releasable from said ester upon smoking of said tobacco, said organic acid having from 3 to 8 carbon atoms.

15. The tobacco recited in claim 14 wherein said sugar compound is an ester of sucrose.

16. The tobacco recited in claim 14 wherein said sugar compound is an ester of an aldose.

17. The tobacco recited in claim 16 wherein said aldose is glucose.

18. The tobacco recited in claim 14 wherein said sugar compound is an ester of a ketose.

19. The tobacco recited in claim 18 wherein said ketose is fructose.

20. A tobacco having improved taste and aroma during smoking and having added thereto a small amount of a substantially nonvolatile ester of an organic hydroxy compound and an aliphatic flavor-producing acid having from 4 to 6 carbon atoms.

21. The tobacco recited in claim 20 wherein said compound is a cyclic hydroxy compound.

22. The tobacco recited in claim 20 wherein said compound is an aromatic hydroxy compound.

23. The tobacco recited in claim 20 wherein said compound is an alicyclic hydroxy compound.

24. The tobacco recited in claim 20 wherein said organic compound is an aliphatic hydroxy compound.

25. The tobacco recited in claim 24 wherein said aliphatic hydroXy compound is a carbohydrate.

26. The tobacco recited in claim 25 wherein said carbohydrate is a sugar.

27. An article of manufacture comprising tobacco and a substantially nonvolatile substance Which, upon smoking the tobacco, releases an organic acid having from 3 to 8 carbon atoms.

28. An article of manufacture comprising smoking tobacco and a substantially nonvolatile ester of an organic hydroxy compound and a flavor-producing acid, releasable upon burning, having at least 3 carbon atoms.

29. The article recited in claim 28 wherein said ester is a sugar ester.

30. A smoking tobacco having added thereto between about 1.0 and about 0.01 per cent by weight (dry basis) of a substantially nonvolatile substance which, upon smoking with the tobacco, releases a volatile organic flavoring acid having from 3 to 8 carbon atoms.

31. A smoking tobacco having added thereto between about 1.0 and about 0.01 per cent by weight (dry basis) of a substantially nonvolatile ester of an organic hydroxy compound and a flavor-producing acid having at least 3 carbon atoms.

32. A smoking tobacco having added thereto between about 1.0 and about 0.01 per cent by weight (dry basis) of a substantially nonvolatile ester of a polyhydroxy compound and a volatile flavor-producing organic acid having from 3 to 8 carbon atoms.

33. A smoking tobacco having added thereto between about 1.0 and about 0.01 per cent by weight (dry basis) of a carbohydrate at least partially esterified with a volatile flavor-producing acid.

34. A smoking tobacco having added thereto between about 1.0 and about 0.01 per cent by weight (dry basis) of a sugar at least partially esterified with a volatile flavorproducing acid having from 3 to 8 carbon atoms.

35. A smoking tobacco having added thereto between about 1.0 and about 0.01 per cent by Weight (dry basis) of glucose at least partially esterified with an organic acid having from 3 to 8 carbon atoms.

36. A smoking tobacco having added thereto between about 1.0 and about 0.01 per cent by weight (dry basis) of glucose 3-methylvalerate.

37. A smoking tobacco having added thereto a small amount of a derivative of malonic acid having the formula /OOOH R-CH COOH wherein R is a hydrocarbon radical having from 1 to 6 (inclusive) carbon atoms.

38. The tobacco recited in claim 37 wherein said small amount is between about 1.0 and about 0.01 per cent by weight (dry basis).

39. The tobacco recited in claim 37 wherein said hydrocarbon radical is selected from the group consisting of alicyclic and aliphatic.

40. The tobacco recited in claim 37 wherein said hydrocarbon radical is a saturated aliphatic radical having from 2 to 4 carbon atoms.

41. A smoking tobacco having added thereto a small amount of a substantially nonvolatile substance relatively stable under normal tobacco storage conditions but which substance will, upon smoking with the tobacco, release in the smoke a volatile flavor-producing acid having from 3 to 8 carbon atoms, said substance being selected from the group consisting of (1) a derivative of malonic acid having the formula COOH R'CH

COOH

wherein R is a hydrocarbon radical having from 1 to 6 (inclusive) carbon atoms, (2) a diketone having the formula R-CO-CHz-CO-R" wherein R is an organic radical and R" is an organic radical having from 2 to 7 (inclusive) carbon atoms, and (3) an ester of said flavor-producing acid.

References Cited in the file of this patent UNITED STATES PATENTS 261,034 Philips July 11, 1882 332,176 Yingling Dec. 8, 1885 937,801 Heddles Oct. 26, 1909 1,338,089 Nelson Apr. 27, 1920 OTHER REFERENCES A Textbook of Organic Chemistry, by A. Bernthsen, page 245, published 1933 by Blackie & Son, Ltd., London.

Condensed Chemical Dictationary, fourth edition, published 1950, by Reinhold Publishing Corporation, New York, N. Y., page 688. 

1. A SMOKING TABACCO HAVING ADDED THERETO A SUBSTANTIALLY NONVOLATILE SUBSTANCE WHICH, UPON SMOKING WITH THE TOBACCO, RELEASES AN ORGANIC ACID HAVING FROM 3 TO 8 CARBON ATOMS. 